how to unlock galaxy s6 bootlader no OEM option - Galaxy S6 Q&A, Help & Troubleshooting

hello
i have galaxy s6 920F zerofltelgt running with: 10 EvolutionX_4.3_zerofltexx-10.0-20200511-1751-OFFICIAL
in the download mode it shoes: g920k
i want to flash stock rom: G920FXXU6ESA1_G920FXSG6ERL1_G920FXXU6ERL2_HOME.tar
but i cant do that with odin because the bootloader in locked
so i need to unlock it
i find some treads telling that i can find OEM unlock option in developer options, but i dont have that option. i think it just exists in stock roms
i also tried: adb reboot bootloader
but it just reboots and doesnt take me to fastboot
i read abou this software to unlock the bootloader: ZYKUFlasher
but i couldnt find a real link to it, it is safe?
so how to unlock the bootloader?
and is it safe to flash 920F version in 0920K?? or it can brick the phone??
Edit:
the bootloader is not locked, but it was preventing of flashing non 920K version.
so i've downloaded 920K stock rom and flashed it via odin successfully (but it did not boot so i flashed TWRP then a custom ROM)

Related

SM-G290F bootloader problem

Hello I have S6 sm-g920f on 5.1.1 ,I was trying to flash engineering bootloader with odin but it always fails on flashing sboot.bin...I downloaded stock 5.1.1 firmware to reflash it fails again on flashing sboot.bin...I was curious to see if I can do something with kies3 so I installed it and went to emergency firmware recovery no devices in the list but it has an option about an emergency recovery code witch I dont even know...Anyone experiencing something like that ?
Thanks in advance
PS no oem unlock option in developer options.

Is the bootloader mistakenly unlocked on my s6 AT&T version?

Hi,
I recently got a brand new s6 G920A AT&T version from an authorized reseller. To my surprise the firmware on it is very old - 5.0.2 with sw version G920AUCU1AOCE
I have heard that this firmware was a pre-release/developer/engineering version of s6 and has unlocked bootloader. Is that true?
How do I find if the bootloader is locked or unlocked in my samsung s6 or for that matter in *any Samsung* phone? Is it possible to check using Odin or some other tool on whether the bootloader is unlocked?
Please let me know your thoughts or ideas! If the above is true, I could perhaps extract the unlocked bootloader and share it with everybody else!!
Thanks!
Alright Interesting...
Use ADB:
=========================================
1. Make to go to about device and tap build number 7 times.
2. Go to developer options (Above About Device)
3. Check usb debugging and oem (Just in case)
4. Connect your phone to your computer via usb cable (Of Course)
5. Download ADB Fastboot if you haven't already =====> https://forum.xda-developers.com/showthread.php?t=2317790
6. Install it and after that it should be set-up
6. Type the command fastboot devices
7. Then type fastboot oem device-info (BTW I am sorry for letting you know now but i think you might need to be in downloading mode or something to use the commands)
8. It should tell you if it is unlocked or not
==============================================
Method 2:
1. Boot up the phone normally then open the phone application and go to the dialer
2. *#*#7378423#*#*
3. Then service info --> configuration
4. Then it should say one of the following:
---------------------------------------------------------------------------------------------------------------------------------
1. Bootloader unlock allowed --Yes >> This means that your Bootloader is Locked
2. Bootloader Unlocked - Yes >> This means that your Bootloader is unlocked
I hope i was helpful to you, if not then i'm sorry to have wasted your time.
Thanks @ROOT67! Let me try both options out and get back on this thread.
ROOT67 said:
Use ADB:
=========================================
1. Make to go to about device and tap build number 7 times.
2. Go to developer options (Above About Device)
3. Check usb debugging and oem (Just in case)
4. Connect your phone to your computer via usb cable (Of Course)
5. Download ADB Fastboot if you haven't already =====> https://forum.xda-developers.com/showthread.php?t=2317790
6. Install it and after that it should be set-up
6. Type the command fastboot devices
7. Then type fastboot oem device-info (BTW I am sorry for letting you know now but i think you might need to be in downloading mode or something to use the commands)
8. It should tell you if it is unlocked or not
==============================================
Method 2:
1. Boot up the phone normally then open the phone application and go to the dialer
2. *#*#7378423#*#*
3. Then service info --> configuration
4. Then it should say one of the following:
---------------------------------------------------------------------------------------------------------------------------------
1. Bootloader unlock allowed --Yes >> This means that your Bootloader is Locked
2. Bootloader Unlocked - Yes >> This means that your Bootloader is unlocked
I hope i was helpful to you, if not then i'm sorry to have wasted your time.
Click to expand...
Click to collapse
Both the methods did not work! Please see for details below.
ROOT67 said:
Use ADB:
=========================================
1. Make to go to about device and tap build number 7 times.
2. Go to developer options (Above About Device)
3. Check usb debugging and oem (Just in case)
4. Connect your phone to your computer via usb cable (Of Course)
5. Download ADB Fastboot if you haven't already =====> https://forum.xda-developers.com/showthread.php?t=2317790
6. Install it and after that it should be set-up
6. Type the command fastboot devices
7. Then type fastboot oem device-info (BTW I am sorry for letting you know now but i think you might need to be in downloading mode or something to use the commands)
8. It should tell you if it is unlocked or not
==============================================
Click to expand...
Click to collapse
I could not put it in fastboot mode. Do we know if the Samsung s6 supports fastboot mode? If so, how to put it in fastboot mode?
Also as a side note, in developer mode under settings, I could find check box for USB debugging but not for OEM. There was another post which said that OEM checkbox was added under developer options only after bootloader lock was introduced in 5.1.1 firmware. Not sure if this is true.
Method 2:
1. Boot up the phone normally then open the phone application and go to the dialer
2. *#*#7378423#*#*
3. Then service info --> configuration
4. Then it should say one of the following:
---------------------------------------------------------------------------------------------------------------------------------
1. Bootloader unlock allowed --Yes >> This means that your Bootloader is Locked
2. Bootloader Unlocked - Yes >> This means that your Bootloader is unlocked
Click to expand...
Click to collapse
When I dial this number, nothing happened. Is there a different number for Samsung s6?
It's not a pre-release/developer/engineering firmware. It's just a really old firmware which released for public officially.
jilebi said:
Both the methods did not work! Please see for details below.
I could not put it in fastboot mode. Do we know if the Samsung s6 supports fastboot mode? If so, how to put it in fastboot mode?
Also as a side note, in developer mode under settings, I could find check box for USB debugging but not for OEM. There was another post which said that OEM checkbox was added under developer options only after bootloader lock was introduced in 5.1.1 firmware. Not sure if this is true.
When I dial this number, nothing happened. Is there a different number for Samsung s6?
Click to expand...
Click to collapse
No other number is available that i know of, like the person above stated it is a old firmware version and with that said i would highly try to prevent any updates from installing. I would love to help you out, but since i have no idea as to what would be needed to tell if the bootloader is unlocked, but i do know since Samsung is against us rooting and using our devices the way we want, it is safe to assume the bootloader is locked and because you have at&t variant. Your best bet to get your device bootloader information is to look around on the XDA forums.
Do you have any details on whether the bootloader was locked or unlocked for this old version? How can one test or check if bootloader is locked?
forumber2 said:
It's not a pre-release/developer/engineering firmware. It's just a really old firmware which released for public officially.
Click to expand...
Click to collapse
jilebi said:
Do you have any details on whether the bootloader was locked or unlocked for this old version? How can one test or check if bootloader is locked?
Click to expand...
Click to collapse
All AT&T branded nearly-new (including S6) Samsung devices has a non-unlockable locked bootloader.
There's no way to test that.
here are a couple of test scenario that i can think of. let me know your thoughts on them
- if the device is rooted, load a custom recovery like TWRP. next, try to boot into custom recovery. if it boots into custom recovery, bootloader is unlocked. if not, try to restore factory recovery using odin.
- if the device is rooted, load a custom ROM. next, try to boot into custom ROM. if it boots into custom ROM, bootloader is unlocked. if not, try to restore factory ROM using odin.
Will these test scenarios work? If not, what are the potential issues you see?
forumber2 said:
All AT&T branded nearly-new (including S6) Samsung devices has a non-unlockable locked bootloader.
There's no way to test that.
Click to expand...
Click to collapse
jilebi said:
here are a couple of test scenario that i can think of. let me know your thoughts on them
- if the device is rooted, load a custom recovery like TWRP. next, try to boot into custom recovery. if it boots into custom recovery, bootloader is unlocked. if not, try to restore factory recovery using odin.
- if the device is rooted, load a custom ROM. next, try to boot into custom ROM. if it boots into custom ROM, bootloader is unlocked. if not, try to restore factory ROM using odin.
Will these test scenarios work? If not, what are the potential issues you see?
Click to expand...
Click to collapse
- There's no custom recovery or custom kernel for SM-G920A, because of the reason I've wrote above.
- Installing a custom ROM doesn't require an unlocked bootloader unless the ROM doesn't require custom kernel. (Custom ROMs for SM-G920A don't require custom kernel (except leaked engineering/debugging kernel from Samsung for disabling dm-verity))
forumber2 said:
- There's no custom recovery or custom kernel for SM-G920A, because of the reason I've wrote above.
- Installing a custom ROM doesn't require an unlocked bootloader unless the ROM doesn't require custom kernel. (Custom ROMs for SM-G920A don't require custom kernel (except leaked engineering/debugging kernel from Samsung for disabling dm-verity))
Click to expand...
Click to collapse
Got it. Thanks. That makes sense.
Here is another option. For making custom recovery, my understanding is that partition info is needed. If the device is rooted e.g. using Pingpong (which works for this Android version), then one can get a partition info and compile TWRP for G920A. If so, can one try to install custom recovery like TWRP and verify if bootloader is locked? It feels to me that this may work. Do you see any flaws?
One possible flaw is that if bootloader is locked, it will prevent recovery from loading. So the phone will be without a working recovery. In that case, can factory recovery be re-installed using Odin?
Also, will any of the above steps trigger the KNOX flag?
jilebi said:
Got it. Thanks. That makes sense.
Here is another option. For making custom recovery, my understanding is that partition info is needed. If the device is rooted e.g. using Pingpong (which works for this Android version), then one can get a partition info and compile TWRP for G920A. If so, can one try to install custom recovery like TWRP and verify if bootloader is locked? It feels to me that this may work. Do you see any flaws?
One possible flaw is that if bootloader is locked, it will prevent recovery from loading. So the phone will be without a working recovery. In that case, can factory recovery be re-installed using Odin?
Also, will any of the above steps trigger the KNOX flag?
Click to expand...
Click to collapse
You don't have to get partition info, and compile TWRP. All S6 variants are using same partition name scheme and there are no difference on TWRP builds between S6 variants (except kernel and DTB).
The bootloader won't allow you to flash any custom recovery image (via Odin or in Android OS). If you could flash it, It won't boot it up anyway.
I don't have any idea about the KNOX trigger on AT&T variant devices, but I think it won't increase anyway.
forumber2 said:
You don't have to get partition info, and compile TWRP. All S6 variants are using same partition name scheme and there are no difference on TWRP builds between S6 variants (except kernel and DTB).
The bootloader won't allow you to flash any custom recovery image (via Odin or in Android OS). If you could flash it, It won't boot it up anyway.
I don't have any idea about the KNOX trigger on AT&T variant devices, but I think it won't increase anyway.
Click to expand...
Click to collapse
Sorry, I perhaps misunderstood from your last post that since custom recovery is not available for G920A it implied its partition info was different from other variants. If it is the same partition structure for all variants, then I guess we can use the TWRP for the G920F international version for which bootloader is unlocked.
Now that we agree that TWRP is available for use on G920A, the next question is how to load it. My thought is that if the device is rooted that means one can use dd at root shell prompt to write TWRP to the recovery partition, without using Odin or the current bootloader. Do you agree?
Not sure I understand why you say that if one could flash TWRP it would not boot anyways. If bootloader is unlocked (which is what we are testing here), then it should boot, right?
jilebi said:
Sorry, I perhaps misunderstood from your last post that since custom recovery is not available for G920A it implied its partition info was different from other variants. If it is the same partition structure for all variants, then I guess we can use the TWRP for the G920F international version for which bootloader is unlocked.
Now that we agree that TWRP is available for use on G920A, the next question is how to load it. My thought is that if the device is rooted that means one can use dd at root shell prompt to write TWRP to the recovery partition, without using Odin or the current bootloader. Do you agree?
Not sure I understand why you say that if one could flash TWRP it would not boot anyways. If bootloader is unlocked (which is what we are testing here), then it should boot, right?
Click to expand...
Click to collapse
A custom recovery is not available for G920A, because no one could try any custom recovery on G920A due to locked bootloader.
Yes you can write the recovery image via dd at root shell prompt.
And yes, If bootloader is unlocked, it will boot it up.
Sorry to ressurect this old thread, but can you (or anybody else who is knowledgeable) answer the following?
1. Since custom recovery is not available for G920A, which of the Tmobile/Sprint/International versions of TWRP custom recovery would you recommend to use for testing if bootloader is unlocked, using either ODIN or dd method?
2. If bootloader is unlocked, you are suggesting below that it should boot up. However, if it is locked, then will the phone still boot up? i.e. if one does not go into recovery mode, will it still boot up or does the bootloader check if both recovery and kernel are signed and if it finds that the recovery is unsigned, will it also prevent the signed kernel from booting up?
Thanks!
forumber2 said:
A custom recovery is not available for G920A, because no one could try any custom recovery on G920A due to locked bootloader.
Yes you can write the recovery image via dd at root shell prompt.
And yes, If bootloader is unlocked, it will boot it up.
Click to expand...
Click to collapse

Bootloader locked, Can't acess Recovery, No OS installed.

Hey guys, i have a problem, my Bootloader is locked and i can't access my recovery, and there is no rom installed, what should i do now? i can't access Developer options to Allow OEM unlock because there is no OS.
am i screwed? or there is something i can do?
Iago Duarte said:
Hey guys, i have a problem, my Bootloader is locked and i can't access my recovery, and there is no rom installed, what should i do now? i can't access Developer options to Allow OEM unlock because there is no OS.
am i screwed? or there is something i can do?
Click to expand...
Click to collapse
Did you ever enable developer options and allow USB debugging? If so, and you can connect to ADB on a PC, you can flash stock firmware back onto the phone.
or try this:
As I didn't have USB debugging enabled I couldn't connect to the phone via ADB, but if you put it into recovery mode you can use Fastboot. Hold down the power key to turn the device off and turn it on while holding down Vol Down to load up recovery mode.
Click to expand...
Click to collapse
However, with locked bootloader there is no room for error in flashing firmware via ADB or you will brick the phone. You have to flash the correct firmware exactly for your phone, with the same level of bootloader you already have or newer. You can't flash Mexico over Brazil or Lollipop over Marshmallow. Has to be exactly what was made for your phone, either what you already had or newer (if it exists).
What OS was installed before?
But WHY is there no ROM installed? What did you do?
The OS installed before was the most recent Stock MM Brazil, i installed the stock rom, it worked, then i wanted to go back to stock recovery, it it worked too, then i wanted to locked my bootloader, i locked, after that i couldn't enter recovery, neither boot to OS.
Iago Duarte said:
The OS installed before was the most recent Stock MM Brazil, i installed the stock rom, it worked, then i wanted to go back to stock recovery, it it worked too, then i wanted to locked my bootloader, i locked, after that i couldn't enter recovery, neither boot to OS.
Click to expand...
Click to collapse
You wanted to re-lock your bootloader? Unlocked bootloader = God mode.
Did you ever have TWRP? You said you wanted to go back to "stock recovery" (not sure why, it's mostly useless compared to TWRP custom recovery.)
I'm not sure why re-locking the bootloader would wipe the OS...
But you can boot to the bootloader screen using the volume and power button and re-flash the stock firmware, using ADB. Here's the link to the newest Brazil Marshmallow for XT1225:
http://ftpeil.eil.com.br/vip/motoro...S24.107-70.2-7_cid12_subsidy-DEFAULT_CFC.xml/
This guy below got out of a jam because he had an unlocked bootloader, which is very forgiving. Locked bootloader is harder.
https://forum.xda-developers.com/moto-maxx/help/maxx-xt1225-br-hard-brick-help-please-t3661803
Yeah, i don't know what happened either, why the **** did my OS got Wiped?
Can i flash the stock rom with the bootloader locked via ADB? how?
Iago Duarte said:
Yeah, i don't know what happened either, why the **** did my OS got Wiped?
Can i flash the stock rom with the bootloader locked via ADB? how?
Click to expand...
Click to collapse
You have to boot to the bootloader screen manually, using the volume + power button trick.
Once on the bootloader screen, when you plug you phone into a PC with ADB installed, it should recognize it.
Then, flash the full stock firmware, from the link above. It's Brazil Marshmallow firmware with December 2016 Security Update. I don't know of any newer right now. You have Brazil XT1225, so that Brazil firmware is compatible with your phone.
But with locked bootloader you have to flash exact same version or newer made for your phone, and you have to enter the commands correctly or you may brick your phone. (When I flashed from Puerto Rico Kitkat to India Lollipop, I messed up. But since my bootloader was unlocked, I just reflashed again, when I realized my mistake.)
If you are not sure of the steps, google Motorola firmware ADB. Here's a couple of excellent tutorials:
How to Manually Official Firmware on any Motorola Device
https://forum.xda-developers.com/dr...force-how-to-manually-flash-official-t3282077
I use this one above. IGNORE where it says you need an unlocked bootloader, because he's talking about cross-region flashing which you are NOT doing. You are flashing your own region firmware.
This one below is by rootjunky and he while he also discusses RSDLite, later in the article he says ADB/fastboot are best as RSDLite can stall.
Motorola Firmware Restore Plus Unbrick
http://www.rootjunky.com/motorola-firmware-restore/
If you get your phone running again, I suggest you unlock the bootloader. There are ways to hide an unlocked bootloader (like Magisk), if that's why you locked it back... But an unlocked bootloader + root makes it YOUR phone and much easier to recover from disasters.
Thanks a lot Chazz, it worked, thanks for the help, really appreciate it, thanks for all the useful tips too.

XT1033, bootloader, can't unlock, can't flash rom, and i really don't know what to do

So here's the history, one beautiful day my XT1033 (Brazil), starts rebooting by itself. Went online, found somethings to do, UNLOCKED THE BOOTLOADER TROUGH THE MOTOROLA SITE, and downgraded to 4.4.4, but I made the mistake of updating it, trough the normal motorola updater. It went black, wouldn't turn on, not even fastboot. Researched a bit more, did a blank flash and then I could access fastboot again. Problem is, somehow my device's bootloader got locked again, and when I tried to "fastboot oem get_unlock_data" , I would get a " couldn't get unlock data!".
So, now I can't flash a ROM , and can't unlock bootloader, is there a way to flash a ROM with it locked? Or to re-unlock the bootloader?
Pls help, I can't stand using a Galaxy pocket neo anymore, HELP ME.
GOD BLESS!
if you can access Bootloader i can recommend just reflash the original stock firmware and u can do that with locked bootloader.

Can't use adb after unlock bootloader again

When I first time unlock the bootloader on my Galaxy S10e (Exynos), I can easily flash custom recovery and ROM, I've tried many custom ROM but then back to OneUI and locked the bootloader
Then the 2nd time I unlocked the bootloader but ADB isn't recognized my phone in download mode anymore, I've tried all kinds of drivers, please help me
(ADB still recognized in recovery and normal OS)
[sorry for no picture]

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